Victims' time discounting 2.5 years after the Wenchuan earthquake: an ERP study.

BACKGROUND: Time discounting refers to the fact that the subjective value of a reward decreases as the delay until its occurrence increases. The present study investigated how time discounting has been affected in survivors of the magnitude-8.0 Wenchuan earthquake that occurred in China in 2008. METHODOLOGY: Nineteen earthquake survivors and 22 controls, all school teachers, participated in the study. Event-related brain potentials (ERPs) for time discounting tasks involving gains and losses were acquired in both the victims and controls. FINDINGS: The behavioral data replicated our previous findings that delayed gains were discounted more steeply after a disaster. ERP results revealed that the P200 and P300 amplitudes were increased in earthquake survivors. There was a significant group (earthquake vs. non-earthquake) × task (gain vs. loss) interaction for the N300 amplitude, with a marginally significantly reduced N300 for gain tasks in the experimental group, which may suggest a deficiency in inhibitory control for gains among victims. CONCLUSIONS: The results suggest that post-disaster decisions might involve more emotional (System 1) and less rational thinking (System 2) in terms of a dual-process model of decision making. The implications for post-disaster intervention and management are also discussed.

Brain dynamic mechanisms of scale effect in visual spatial attention.

The dynamic mechanisms of the early event-related potential scale effect of different attentive regions in the brain was studied. The paradigm of this experiment is the precue-target visual search paradigm by event-related potential technique. The results showed that the reaction time was shortened with the reduction of cue scale, a cue to how big the search area would be, and fixed target stimulus, while the amplitudes of P1 and N1 components of event-related potentials increased. These results not only provided the electrophysiological evidences that supported the zoom-lens theory, but also indicated that the zoom-lens effect happened at the early selected attention period. The results also showed that there existed two kinds of separation in the P2 effect.